Matching network

Figure C2.13.3. Schematic illustrations of various electric discharges (a) DC-glow discharge, R denotes a resistor (b) capacitively coupled RF discharge, MN denotes a matching network (c), (d) inductively coupled RF discharge, MN denotes matching network (e) dielectric barrier discharge.

The lower electrode is coupled via a fl-type matching network to a 13.56-MHz generator. This network provides power matching between the RF power cable (50 2) and the plasma. Power levels are between 1 and 100 W, or between 6 and 600 mW/cm, using the area of the powered electrode. 

The subtractive method was adapted from Horwitz [182], and is easiest in use. The principle is to measure the power delivered to the system, including the tuned matching network, in the case that the discharge is on (Ptot) and in the case that it is off, i.e. when the system is evacuated (Pvac)- with the constraint that in both cases Plot and Pvac are measured for the same electrode voltage Vpp. The matcher efficiency [181] or power transfer efficiency r]p [183] then is defined as... 

Of course, care should be taken when comparing the experimental data and the modeling results the model is an approximation, and the experiment has its uncertainties. The most important approximation is that the model is one-dimensional. A main uncertainty of the experiment is the relation between source power and plasma power (see Section 1.3.2.3). The source power is defined as the power delivered by the power generator. In experiments, the source power is a discharge setting (Table IV). The plasma power is the power dissipated by the plasma. As a rule, this plasma power is smaller than the source power, due to losses in the matching network, which matches the plasma impedance to the impedance of the source power generator, viz., 50 [180]. From comparison of experimental data... 

FIG. 35. Vertical cross section of the reaction chamber equipped with the mass spectrometer system. Indicated are QMF. the quadmpole mass filter ESA. the electrostatic analyzer CD, the channeltron detector DE, the detector electronics DT, the drift tube lO, the ion optics TMP, the turbomolecular pump PR, the plasma reactor and MN. the matching network. 

Madan et al. [515] have presented the effect of modulation on the properties of the material (dark conductivity and photoconductivity) and of solar cells. They also observe an increase in deposition rate as a function of modulation frequency (up to 100 kHz) at an excitation frequency of 13.56 MHz, in their PECVD system [159]. The optimum modulation frequency was 68 kHz, which they attribute to constraints in the matching networks. Increasing the deposition rate in cw operation of the plasma by increasing the RF power leads to worse material. Modulation with a frequency larger than 60 kHz results in improved material quality, for material deposited with equal deposition rates. This is also seen in the solar cell properties. The intrinsic a-Si H produced by RF modulation was included in standard p-i-n solar cells, without buffer or graded interface layers. For comparison, solar cells employing layers that were deposited under cw conditions were also made. At a low deposition rate of about 0.2 nm/s, the cw solar cell parameters... 

Wide range Dunmore sensors can he made with a cluster of narrow range sensors in a common housing, mated with an electrical matching network. This arrangement, however, usually results in a rather bulky sensor. 

Remark 2 Since the target of minimum number of matches is not used as a heuristic to determine the matches and heat loads with either the MILP transshipment model or the vertical MILP transshipment model, the above problem statement addresses correctly the simultaneous matches-network optimization. 

In the following section, we will discuss the approach proposed by Floudas and Ciric (1989) for simultaneous matches-network optimization. 

The basic idea in the simultaneous matches-network optimization approach of Floudas and Ciric... 

Remark 1 The above statement corresponds to the simultaneous consideration of all steps shown in Figure 8.20, including the optimization loop of the HRAT. We do not decompose based on the artificial pinch-point which provides the minimum utility loads required, but instead allow for the appropriate trade-offs between the operating cost (i.e., utility loads) and the investment cost (i.e., cost of heat exchangers) to be determined. Since the target of minimum utility cost is not used as heuristic to determine the utility loads with the LP transshipment model, but the utility loads are treated as unknown variables, then the above problem statement eliminates the last part of decomposition imposed in the simultaneous matches-network optimization presented in section 8.5.1. 

Remark 3 For (ii)-(iv), the hyperstructure approach presented in the section of simultaneous matches-network optimization will be utilized. 

Note that the binaries yij multiply Aij in the objective function for the same reasons that we wrote the objective function of case I of the simultaneous matches-network optimization (see section 8.5.1.4). 

A. R. Ciric and C. A. Floudas. Application of the simultaneous match-network optimization approach to the pseudo-pinch problem. Comp. Chem. Eng., 14 241,1990. 

Figure 8.2.13 Schematic of the probehead using four decoupled coils, as reported in Reference [19] (a) top-down view (b) side view. Each coil and corresponding matching network is oriented at 90° with respect to its nearest neighbour in order to minimize coupling. Reprinted with permission From Li, Y., Wolters, A., Malaway, P., Sweedler, J. V. and Webb, A. G., Anal. Chem., 71, 4815—4820 (1999). Copyright (1999) American Chemical Society...

Figure 8.2.17 Photograph of a two-coil, multi-tuned probehead, with two solenoids arranged vertically. The impedance matching networks are shielded in copper boxes...

We have used several different frequencies between 0.25 and 2 MHz. The use of lower frequencies not only increases the focal spot size but also reduces the number of erythrocyte extravasations per unit area (9). The reduction in the diameter of the transducer, or increase in the radius of curvature, also increases the focal spot size. Examples of the 50% focal spot dimensions for different transducers are given in Table 2. The electrical impedance of the transducer is, typically, matched to the output impedance of the amplifier by an external LC-matching network to allow optimum power transfer. Although, we manufactured our own transducers in-house, custom MRI compatible transducers can be purchased from several manufacturers such as Imasonic, Inc. (Besancon, France). 

Impedance-matching network (passive) An interconnected arrangement of components, the most important of which is an inductor (often tunable), that matches the impedance of a device (e.g., one transducer of an AW sensor) to the impedance of the instrumentation (e.g., an amplifier) to which it is to be connected. This maximizes the power that can be transferred. 

It appears then that the relative rates of the reactions taking place at the surface of the resist under high-bias conditions are quite different from those occurring under low bias. In part this is related to the overall energy discharged in the plasma. Since a fully matched network was used in these studies, the RF power determines the electrode self-bias at constant... 

The tubular-type plasma reactor system used in the study consists of a reactor chamber, power supply, monomer feed, and pumping-out units, as depicted in Figure 19.1. One side of the glass tube is connected to a monomer inlet and the other side to a vacuum pump with O-ring joints. A radio frequency power generator of 13.56 MHz is coupled to two capacitive copper electrodes, which are 1 cm wide and 6 cm apart. The radio frequency power was controlled by an L-C matching network and monitored by power meter. 

An rf power at 13.56 MHz was supplied to the coil (15) by a crystal controlled generator with a power amplifier (Electronic Navigation Ind., A-300) through an LC parallel-resonance type impedance matching network. The power and SWR were monitored with a through-line wattmeter (Leader Test Instrument, LPN-885). 

The radiofrequency power is provided by a Heathkit model DX-60B r.f. generator, run at a frequency of 13.56 MHz, via a National Radio Company Inc. model NCL-2000 power amplifier and a Bendix Corporation model 263 power meter. This system can deliver 0-300 watts of radiofrequency power maintained at a constant level by a power level control unit. The output of the r.f. power unit is impedance matched to the cathode of the reactor via an LC matching network. 

Fig. 2.3.8 Surface coil with symmetrical matching network and detuning diodes. Adapted from [Krel] with permission from Publicis MCD.

Plasma Power Supply Plasma Therm, Inc., Model NFS-2500 D with Model AMN-3000 E impedance matching network. 

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